The present invention relates to signal transmitting means, in particular to self-contained apparatuses for transmitting digital signals and remote control (RC) systems on their basis.
The invention may be used to create self-contained maintenance-free signal transmitters, beakons, signaling and transmitting devices in safety systems, wireless sensors in industrial automation systems, and remote control systems of consumer and industrial equipment.
A known self-contained coded radio-frequency signal transmitter for safety systems comprises a piezoelectric cell for generating electric charges under the application of mechanical stress thereto, a unit for generating and transmitting radio-frequency signals on air and a circuit for supplying power to said unit from the piezoelectric cell (see U.S. Pat. No. 5,572,190, published Nov. 5, 1996).
A deficiency of the known transmitter is that a relatively small electric charge generated by the piezoelectric cell when exposed to mechanical stress flows virtually unchanged to a low-frequency filter capacity which serves as a peculiar kind of buffer charge storage to supply the following unit for generating and transmitting coded radio-frequency signals. Low voltage (5-12V) at output of the low-frequency filter, suitable to supply said signal transmission unit, is generated owing to a significant voltage drop across active component of the filter, this in turn reducing the output power of the circuit. A threshold element and a silicon rectifier in this circuit affect only the shape and polarity of the current pulse from the piezoelectric cell without increasing the total charge in initial current pulse. Non-ideal nature of the silicon rectifier used in the circuit, specifically, a low diode breakdown voltage (several thousand volts) and electrical leaks from back-biased diodes, reduces a permissible operating voltage magnitude at its input and restricts thereby the possibility of obtaining sufficiently great current pulses in the circuit. As the result, the charge stored in the low-frequency filter capacity will be relatively small, this reducing efficiency of the electric supply circuit of the known radio-frequency signal transmitter as a whole.
Also known in the art are various RC devices and systems for electric apparatuses, including a lighting fixture RC system (see U.S. Pat. No. 3,971,028, published Jul. 20, 1976), a suspended fan RC system (see U.S. Pat. No. 4,371,814, published Feb. 1, 1983), TV and audio receiver RC system (see U.S. Pat. No. 3,928,760, published Dec. 23, 1975), a transmitter for a car lock RC system (see U.S. Pat. No. 5,592,169, published Jan. 7, 1997).
In particular, the car lock RC system disclosed in U.S. Pat. No. 5,592,169, comprises a self-contained coded RC signal transmitter, a receiver and a lock control unit. The receiver in the RC system receives energy from the same electric circuit as the load controlled thereby, the lock, and the self-contained RC signal transmitter is provided with an independent electric power supply, a battery or rechargeable battery.
The necessity of periodic expenditures for buying batteries, recharging rechargeable batteries and providing timely service to the self-contained transmitter, along with economic and environmental problems involved in utilization of spent batteries, are basic disadvantages of such RC systems that restrict their wide use.
Attempts have been taken to design control systems wherein a transmitter is supplied from piezoelectric cells, e.g. an electronic toy control unit (see U.S. Pat. No. 4,612,472, published Sep. 16, 1986). In the device, however, the transmitted signal has no digital coding of information which is required to control different functions of an actuator of a controlled object, and the charge from the piezoelectric cell is directly used by the transmitting apparatus without any preliminary processing, i.e. very inefficiently.
DE 4034100 teaches an apparatus for storing energy of natural lightning. The apparatus uses a reducing transformer connected, via a bridge rectifier, to a accumulation capacitor. However, the application of such design of the secondary transformer coil and the bridge rectifier is not quite efficient because, when charging the accumulation capacitor, the current pulse energy of the secondary coil is lost at two series-connected forward-biased diodes.
Furthermore, the use of natural lightning as the charge generator for compact remote control transmitters is infeasible.
Numerous documents teach various embodiments of charge generators, information generation and transmission units, and information transmission channels (see U.S. Pat. No. 5,012,223; U.S. Pat. No. 5,563,600; SU 1,003,129; GB 2164219; GB 2177527 and EPO 513443). The aforementioned documents, however, are lacking information of the possibility to use the features disclosed in them, either individually or in combination, for providing battery-free self-contained remote control signal transmitters, and information of ways of designing and technical embodiments of battery-free self-contained remote control signal transmitters and remote control systems on their basis.
The inventors are unaware of employment of piezoelectric cells or other charge generators to provide RC systems for consumer or industrial apparatuses.
The object of the present invention is to provide a self-contained digital signal transmitter which would not need periodic replacement or recharging of electric power supply, and would have an efficient circuit supplied from a charge generator, which in turn would enable the creation of RC systems for electric apparatuses, data acquisition systems and warning systems, with the possibility of long-term integration of RC signal transmitters, like traditional wall-board switches, in unmanned structures and constructions.
The above object is attained in a self-contained digital signal transmitter comprising: an electric power supply including an electric charge generator with an actuation means, and a digital signal generation and transmission unit; the signal transmitter further comprising an electric charge energy converter having an input connected to an output of the charge generator, and an output connected to an input of the digital signal generation and transmission unit; the electric charge energy converter being adapted to increase initial number of electric charges provided from the generator, and reduce potential of electric charges stored at the output of the converter.
The output of the converter may further include an electric charge storage in the form of, for example, a capacitor, for buffering the electric power from the digital signal generation and transmission unit.
In an embodiment of the self-contained transmitter, the electric charge energy converter is a reducing transformer, a primary coil of which is connected to an output of the electric charge generator, and a secondary coil comprises two coils and is connected, via a full-wave rectifier, to the electric charge storage, which is more efficient than the design of the converter taught in DE 4034100. The converter is efficient when the charge generator produces short high-energy current pulses.
In another embodiment of the self-contained transmitter, the electric charge energy converter is a semiconductor converter having an input region coupled to an output of the electric charge generator, formed by a back-biased p-n-junction and intended for storing charges from the electric charge generator and producing an avalanche breakdown process when a threshold voltage is exceeded across said p-n-junction, and an output region of the semiconductor converter, formed by a region for separating and storing secondary charges produced as the result of the avalanche breakdown, and connected, via a rectifier, to the electric charge storage. The input region of the semiconductor converter may be formed by other structures different from said p-n-junction, for example, by a transistor or thyristor structure which would provide a more pronounced electric charge avalanche multiplication process.
The self-contained transmitter may further comprise an electric charge energy converter formed by a battery of capacitors and provided with a switching device to switch the capacitors from series connection required to store charges from the charge generator, to parallel connection enabling the reduction in the charge potential at the converter output, and the use, in full measure, of the total charge stored in each capacitor separately. In this embodiment electric charge energy generated by the charge generator is used most efficiently.
The electric charge generator may be a piezoelectric cell, a triboelectric cell. It is also advantageous to use such an electric charge generator with high electric potential and practically unexhaustable capacity, as e.g. a radioactive source of charged particles which may be in the form of a capacitor, one plate of which comprises a radioactive material emitting charged xcex2-particles, and another plate is a collector of the charged xcex2-particles.
The latter two electric charge generators generate charges relatively slow, so the series of the described above converters may be advantageously supplemented with a short pulse former connected between the output of the electric charge generator and an input of the electric charge energy converter, said short pulse former being in the form of a gas-discharge tube, or a semiconductor threshold element, for example, a thyristor.
The digital signal generation and transmission unit in a self-contained transmitter in accordance with the invention may be adapted to transmit a radio-frequency signal, an optical signal, and an acoustic signal. In a number of systems for transmitting digital codes over great distances, the optical embodiment of the self-contained transmitter is rather efficient with the use of a laser signal emitter.
The present invention permits designing self-supporting beakons in which the electric charge generator may be a radioactive source of charged particles, so that such apparatuses may be operated, substantially service-free, in space and in marine navigation systems.
In part of a remote control system the above technical result is attained also due to the fact that in the RC system comprising an RC signal transmitter and a control unit for controlling at least one electric apparatus including a signal receiver connected with said transmitter through a communication channel, in accordance with the invention, the RC signal transmitter is a self-contained digital signal transmitter according to any one of the above-described embodiments.
The communication channel in the RC system may be provided by galvanic wire coupling, wire communication with various types of galvanic isolation, or a radio-frequency channel, an optical channel or an acoustic channel.
In the RC system, the controlled electric apparatuses may include lighting fixtures, apparatuses with an electrical actuator, home electronics apparatuses, predominantly heaters, refrigerators and air conditioners, warning and alarm apparatuses, and in particular a computer for processing and storing information received from self-contained digital signal transmitters.
An important feature of such RC system is that the RC signal transmitter may be adapted to be integrated in walls of constructions and other unmanned engineering structures, because such charge generators as, for example, piezoelectric cells, triboelectric cells, radioactive sources of charged particle do not require service such as periodic replacement or recharging of electrolytic cells.
The principle possibility of attaining the aforementioned result may be explained on the premise that the energy conservation law is observed for the conversion corresponding to the invention, which looks, in ideal form, as q*Uin=Q*Uout, where q and Uin are, respectively, the charge and its potential at input of the converter, and Q and Uout are, respectively, the charge and its potential at output of the converter. On the basis of this condition it may be assessed that to increase (multiply) the number of charges at the converter output, i.e. for condition Q greater than q, it is required that the potential Uin at the converter input would exceed the potential Uout at its output. Condition Uin greater than Uout can be rather easily realized technically since the potential of charges produced by a charge generator, such as a piezoelectric cell or a triboelectric cell, is inversely related to the self-capacity or load capacity, and may reach several thousand volts, whereas the potential needed to supply circuitry of the transmitter is only a few volts. Efficiency of the charge number multiplication process will be defined by efficiency of the converter in the process of transporting the initial charge electric energy from the converter input to its output.